FRAX - A Fracture Risk Calculator

Fracture Risk Assessment Tool

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FRAX Explained

FRAX is a tool that was developed by the World Health Organization in 2008 to assess fracture risk. FRAX integrates clinical risk factors and bone mineral density (BMD) at the femoral neck to calculate a 10-year fracture probability for men and women. Simply put, it's a fracture risk calculator.

The models used to develop the FRAX calculator were derived from studying patient populations in North America, Europe, Asia, and Australia.

There are paper versions of FRAX available but a free online FRAX tool exists as well. The web version is available in various languages.

According to Postgraduate Medicine, "Osteoporosis-related fractures (low-trauma or fragility fractures) cause substantial disability, health care costs, and mortality among postmenopausal women and older men. Epidemiologic studies indicate that at least half the population burden of osteoporosis-related fractures affects persons with osteopenia (low bone density), who comprise a larger segment of the population than those with osteoporosis. The public health burden of fractures will fail to decrease unless the subset of patients with low bone density who are at increased risk for fracture are identified and treated."

Knowing your 10-year fracture probability allows you and your doctor to make treatment decisions. The goal, if treatment is indicated, would be to lower your risk of bone fracture and to prevent osteoporosis.

Because osteoporosis is a silent disease, meaning that no symptoms typically are apparent until a fracture occurs, lowering risk is essential. The National Osteoporosis Foundation recommends treating patients with FRAX 10-year risk scores of  'greater than or equal to 3 percent' for hip fracture or 'greater than or equal to 20 percent' for major osteoporotic fracture to reduce fracture risk.

The FRAX Questionnaire

FRAX asks 12 questions and then calculates your 10-year fracture probability. The information that is input to determine your fracture risk includes:

  • Age or Date of Birth
  • Male or Female
  • Weight in kilograms
  • Height in centimeters
  • Previous fracture (no or yes)
  • Parent fractured hip (no or yes)
  • Current smoking (no or yes)
  • Glucocorticoids (no or yes)
  • Rheumatoid arthritis (no or yes)
  • Secondary osteoporosis (no or yes)
  • Alcohol - 3 or more units per day (no or yes)
  • Femoral neck bone mineral density - BMD in g/cm(squared)

The FRAX calculator asks very specific questions related to glucocorticoids, rheumatoid arthritis, secondary osteoporosis, and alcohol use. To answer yes to the glucocorticoid question, you must have taken three months or more of prednisolone at 5 mg a day (or the equivalent dose of other steroids). "Yes" for rheumatoid arthritis means you have a confirmed diagnosis. "Yes" to secondary osteoporosis means you have a condition that is strongly linked to osteoporosis.

The Bottom Line

The FRAX calculator determines the 10-year fracture probability for an individual patient. By doing so, the calculator is essentially finding patients who need intervention or treatment to lower that probability.

The results can help manage the risk of osteopenia, osteoporosis, and bone fracture. Osteoporosis is the cause of 1.5 million fractures each year. About 54 million Americans have osteoporosis or low bone mass which increases the risk for developing osteoporosis. Studies suggest that approximately one in two women and up to one in four men age 50 and older will break a bone due to osteoporosis at some point during their life. That said, while it is an effective tool for identifying the high risk group of patients, FRAX does not force diagnostic or treatment decisions on the doctor.

FRAX is also available as an iPhone app for $5.99.

Sources:

FRAX. WHO Fracture Risk Assessment Tool.

FRAX Calculation Tool. WHO Fracture Risk Assessment Tool.

Hashimoto K. et al. Clinical Calcium. Usefulness of FRAX and future issues in women's health. 2009 Dec;19(12):1742-8

Siris ES  et al. Primary care use of FRAX: absolute fracture risk assessment in postmenopausal women and older men. Postgraduate Medicine. 2010 Jan;122(1):82-90.

What Is Osteoporosis? National Osteoporosis Foundation.

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